Added option to cache results of JRE extract & minimize, to speedup build times.

Author: code-disaster

README.md

@@ -30,14 +30,15 @@ java -jar packr.jar \
 | Parameter | Meaning |
 | --- | --- |
 | platform | one of "windows32", "windows64", "linux32", "linux64", "mac" |
-| jdk | ZIP file location or URL to ZIP file of an OpenJDK or Oracle JDK build containing a JRE. Prebuild OpenJDK packages can be found at https://github.com/alexkasko/openjdk-unofficial-builds. You can also specify a directory to an unpacked JDK distribution. E.g. using ${java.home} in a build script|
+| jdk | directory, ZIP file, or URL to ZIP file of an OpenJDK or Oracle JDK build containing a JRE. Prebuild OpenJDK packages can be found at https://github.com/alexkasko/openjdk-unofficial-builds. You can also specify a directory to an unpacked JDK distribution. E.g. using ${java.home} in a build script|
 | executable | name of the native executable, without extension such as ".exe" |
 | classpath | file locations of the JAR files to package |
 | mainclass | the fully qualified name of the main class, using dots to delimit package names |
 | vmargs | list of arguments for the JVM, without leading dashes, e.g. "Xmx1G" |
 | resources (optional) | list of files and directories to be packaged next to the native executable |
 | minimizejre | minimize the JRE by removing directories and files as specified by an additional config file. Comes with a few config files out of the box. See below for details on the minimization config file. |
 | output | the output directory |
+| cachejre (optional) | An optional directory to cache the result of JRE extraction and minimization. See below for details. |
 | icon (optional, OS X) | location of an AppBundle icon resource (.icns file) |
 | bundleidentifier (optional, OS X) | the bundle identifier of your Java application, e.g. "com.my.app" |
 | verbose | prints more status information during processing, which can be useful for debugging |
@@ -159,6 +160,12 @@ Packr comes with two such configurations out of the box, [`soft`](https://github
 
 There's also a new, *experimental* configuration, [`oraclejre8`](https://github.com/libgdx/packr/blob/master/src/main/resources/minimize/oraclejre8), which reduces size of an Oracle 8 JRE following Oracle's redistribution rules described [here](http://www.oracle.com/technetwork/java/javase/jre-8-readme-2095710.html). It also repacks JAR files, reducing (unpacked) JRE size from about 180 mb to 70 mb. **This version is pretty much untested, so please use with care!**
 
+### Cache
+
+Extracting and minimizing a JRE can take quite some time. If the `cachejre` option is used, the result of these operations is cached in the given folder, and can be reused in subsequent runs of packr.
+
+As of now, packr doesn't do any elaborate checks to validate the content of this cache folder. So if you update the JDK, or change the minimize profile, you need to empty or remove this folder manually to force a change.
+
 ### Classpath
 
 Minimization aside, packr also removes all dynamic libraries which do not match the target platform from your project JAR file(s):

src/main/java/com/badlogicgames/packr/Packr.java

@@ -51,12 +51,10 @@ public void pack(PackrConfig config) throws IOException {
 
 		writeConfig(output);
 
-		copyJRE(output);
+		copyAndMinimizeJRE(output, config);
 
 		copyResources(output);
 
-		PackrReduce.minimizeJre(output, config);
-
 		PackrReduce.removePlatformLibs(output, config);
 
 		System.out.println("Done!");
@@ -197,44 +195,74 @@ private void writeConfig(PackrOutput output) throws IOException {
 		}
 	}
 
-	private void copyJRE(PackrOutput output) throws IOException {
+	private void copyAndMinimizeJRE(PackrOutput output, PackrConfig config) throws IOException {
 
-		File jdkFile;
-		boolean fetchFromRemote = config.jdk.startsWith("http://") || config.jdk.startsWith("https://");
+		boolean extractToCache = config.cacheJre != null;
+		boolean skipExtractToCache = false;
 
-		// add JRE from local or remote zip file
-		if (fetchFromRemote) {
-			System.out.println("Downloading JDK from '" + config.jdk + "' ...");
-			jdkFile = new File(output.resourcesFolder, "jdk.zip");
-			InputStream in = new URL(config.jdk).openStream();
-			OutputStream outJdk = new FileOutputStream(jdkFile);
-			IOUtils.copy(in, outJdk);
-			in.close();
-			outJdk.close();
-		} else {
-			jdkFile = new File(config.jdk);
+		// check if JRE extraction (and minimize) can be skipped
+		if (extractToCache && config.cacheJre.exists()) {
+			if (config.cacheJre.isDirectory()) {
+				// check if the cache directory is empty
+				String[] files = config.cacheJre.list();
+				skipExtractToCache = files != null && files.length > 0;
+			} else {
+				throw new IOException(config.cacheJre + " must be a directory");
+			}
 		}
 
-		System.out.println("Unpacking JRE ...");
-		File tmp = new File(output.resourcesFolder, "tmp");
-		PackrFileUtils.mkdirs(tmp);
+		// path to extract JRE to (cache, or target folder)
+		File jreStoragePath = extractToCache ? config.cacheJre : output.resourcesFolder;
 
-		if (jdkFile.isDirectory()) {
-			PackrFileUtils.copyDirectory(jdkFile, tmp);
+		if (skipExtractToCache) {
+			System.out.println("Using cached JRE in '" + config.cacheJre + "' ...");
 		} else {
-			ZipUtil.unpack(jdkFile, tmp);
-		}
+			// path to extract JRE from (folder, zip or remote)
+			boolean fetchFromRemote = config.jdk.startsWith("http://") || config.jdk.startsWith("https://");
+			File jdkFile = fetchFromRemote ? new File(jreStoragePath, "jdk.zip") : new File(config.jdk);
+
+			// download from remote
+			if (fetchFromRemote) {
+				System.out.println("Downloading JDK from '" + config.jdk + "' ...");
+				try (InputStream remote = new URL(config.jdk).openStream()) {
+					try (OutputStream outJdk = new FileOutputStream(jdkFile)) {
+						IOUtils.copy(remote, outJdk);
+					}
+				}
+			}
 
-		File jre = searchJre(tmp);
-		if (jre == null) {
-			throw new IOException("Couldn't find JRE in JDK, see '" + tmp.getAbsolutePath() + "'");
-		}
+			// unpack JDK zip (or copy if it's a folder)
+			System.out.println("Unpacking JRE ...");
+			File tmp = new File(jreStoragePath, "tmp");
+			PackrFileUtils.mkdirs(tmp);
 
-		PackrFileUtils.copyDirectory(jre, new File(output.resourcesFolder, "jre"));
-		PackrFileUtils.deleteDirectory(tmp);
+			if (jdkFile.isDirectory()) {
+				PackrFileUtils.copyDirectory(jdkFile, tmp);
+			} else {
+				ZipUtil.unpack(jdkFile, tmp);
+			}
+
+			// copy the JRE sub folder
+			File jre = searchJre(tmp);
+			if (jre == null) {
+				throw new IOException("Couldn't find JRE in JDK, see '" + tmp.getAbsolutePath() + "'");
+			}
+
+			PackrFileUtils.copyDirectory(jre, new File(jreStoragePath, "jre"));
+			PackrFileUtils.deleteDirectory(tmp);
+
+			if (fetchFromRemote) {
+				PackrFileUtils.delete(jdkFile);
+			}
+
+			// run minimize
+			PackrReduce.minimizeJre(jreStoragePath, config);
+		}
 
-		if (fetchFromRemote) {
-			PackrFileUtils.delete(jdkFile);
+		if (extractToCache) {
+			// if cache is used, copy again here; if the JRE is cached already,
+			// this is the only copy done (and everything above is skipped)
+			PackrFileUtils.copyDirectory(jreStoragePath, output.resourcesFolder);
 		}
 	}
 

src/main/java/com/badlogicgames/packr/PackrCommandLine.java

@@ -61,6 +61,9 @@ public interface PackrCommandLine {
 	@Option(description = "minimize JRE by removing folders and files specified in config file", longName = "minimizejre", defaultToNull = true)
 	String minimizeJre();
 
+	@Option(description = "folder to cache bundled JRE, to speedup builds", longName = "cachejre", defaultToNull = true)
+	File cacheJre();
+
 	@Option(description = "additional files and folders to be packed next to the executable", longName = "resources", defaultToNull = true)
 	List<File> resources();
 

src/main/java/com/badlogicgames/packr/PackrConfig.java

@@ -66,6 +66,7 @@ static Platform byDesc(String desc) throws IOException {
 	public String mainClass;
 	public List<String> vmArgs;
 	public String minimizeJre;
+	public File cacheJre;
 	public List<File> resources;
 	public File outDir;
 	public File iconResource;
@@ -125,6 +126,10 @@ public PackrConfig(PackrCommandLine commandLine) throws IOException {
 			minimizeJre = commandLine.minimizeJre();
 		}
 
+		if (commandLine.cacheJre() != null) {
+			cacheJre = commandLine.cacheJre();
+		}
+
 		resources = appendTo(resources, commandLine.resources());
 
 		if (commandLine.outDir() != null) {
@@ -163,6 +168,9 @@ private void readConfigJson(File configJson) throws IOException {
 		if (json.get("minimizejre") != null) {
 			minimizeJre = json.get("minimizejre").asString();
 		}
+		if (json.get("cachejre") != null) {
+			cacheJre = new File(json.get("cachejre").asString());
+		}
 		if (json.get("resources") != null) {
 			resources = toFileArray(json.get("resources").asArray());
 		}
@@ -177,7 +185,7 @@ private void readConfigJson(File configJson) throws IOException {
 
 	private <T> List<T> appendTo(List<T> list, List<T> append) {
 		if (list == null) {
-			return append != null ? append : new ArrayList<T>();
+			return append != null ? append : new ArrayList<>();
 		}
 
 		if (append != null) {

src/main/java/com/badlogicgames/packr/PackrReduce.java

@@ -29,7 +29,7 @@
  */
 class PackrReduce {
 
-	static void minimizeJre(PackrOutput output, PackrConfig config) throws IOException {
+	static void minimizeJre(File output, PackrConfig config) throws IOException {
 		if (config.minimizeJre == null) {
 			return;
 		}
@@ -45,7 +45,7 @@ static void minimizeJre(PackrOutput output, PackrConfig config) throws IOExcepti
 			JsonArray reduceArray = minimizeJson.get("reduce").asArray();
 			for (JsonValue reduce : reduceArray) {
 				String path = reduce.asObject().get("archive").asString();
-				File file = new File(output.resourcesFolder, path);
+				File file = new File(output, path);
 
 				if (!file.exists()) {
 					if (config.verbose) {
@@ -57,7 +57,7 @@ static void minimizeJre(PackrOutput output, PackrConfig config) throws IOExcepti
 				boolean needsUnpack = !file.isDirectory();
 
 				File fileNoExt = needsUnpack
-						? new File(output.resourcesFolder, path.contains(".") ? path.substring(0, path.lastIndexOf('.')) : path)
+						? new File(output, path.contains(".") ? path.substring(0, path.lastIndexOf('.')) : path)
 						: file;
 
 				if (needsUnpack) {
@@ -112,7 +112,7 @@ static void minimizeJre(PackrOutput output, PackrConfig config) throws IOExcepti
 
 				JsonArray removeFilesArray = remove.asObject().get("paths").asArray();
 				for (JsonValue removeFile : removeFilesArray) {
-					removeFileWildcard(output.resourcesFolder, removeFile.asString(), config);
+					removeFileWildcard(output, removeFile.asString(), config);
 				}
 			}
 		}